package com.xucan.fanxingx.tongpeifu;

public class Demo {
    //通配符
    //?代表任意类型
    //? extends E  E的子类
    //? super E  E的父类

    public static void main(String[] args) {
        printSound(new Dog());

    }

    private static void printSound(Dog dog) {

    }
}
